[1] Cincinnati Childrens Hosp Med Ctr, Heart Inst, Cincinnati, OH 45229 USA
[2] Cincinnati Childrens Hosp Med Ctr, Cincinnati Fetal Ctr, Maternal Fetal Med, Cincinnati, OH 45229 USA
[3] Good Samaritan Hosp, Dept Obstet & Gynecol, Cincinnati, OH USA
[4] Cincinnati Childrens Hosp Med Ctr, Dept Biostat & Epidemiol, Cincinnati, OH 45229 USA